Topic: Greetings... my new mic preamp.

[Nick's Picks]

Very, very nice.
its great to see folks like yourself discover us,...and find excitement w/the target market.
bravo!

I'd throw down w/a set of features that I'd like...but you've got everything covered basically.
Now, here are the marketing aspects of our community.  perhaps these points will dictate/drive functionality of said preamp.
as for a name, I say keep it what you have.  maybe throw a "FV field version" in there.


- we strive for sound quality.  we like our preamps to be quick and clean.  no noise.  no commissions.  Not to say we dont like our "flavor" too, but there are many preamps out there w/that.

- we like "in the bag friendly".  recessed controls, side accessable cables, exteranal DC power that is easy to run off of Lithium Ion products (like DVD batteries for those portable players) that output 9-12v.

- 4 channel recording is a hot ticket right now.  lots of people doing it, or wanting to.

- "dongle" cables to cut down on space.  Instead of various I/Os and the room that the jacks require, think about a single 5pin output, either w/switchcraft mini's (ta5) or full sized 5pin XLRs.  then you have various breakout cables which you can market or leave to the cable makers (we have several wonderful companies here on the list making custom cables).  This way you can have balanced/unbalanced and any flavor of output from the preamp to recorder. 

- as mentioned...lights are not all that relevant.  one to show its "on".  one to show that its "going to die" and one to show that its clipping, or close to it.  Many people like to run their gear "hot".  so a light at -2db would be perfect.  Lets us know what the box is doing before sending a signal out to a recording deck.

- small, light, easily concealable.
- cost effective.  put the investment into the internal parts and dont sweat the exterior.

Now, if  you really want to get fancy and have a product that no-body else offers:
Many (and I mean many) people here run modular microphones with "active" cables.  Think schoeps collette, Neumann KM100 series..etc.
build a preamp that can eliminate the need for the preamp body of these modular systems. 
Something lemo style connectors for the Schoeps active cables and Neumann ka style older active cables.
There are only two boxes like this in existence. 
1. the schoeps VMS (which will only work w/the schoeps mics, of course)
2. Sonosax "lemosax" version, no longer in production.  This would take the schoeps and the neumanns, I believe.

We also have new modular kits w/active cable solutions in the pipeline from:
- Beyerdynamic
- VMlabs
- Peluso (cemc6 condensers)

and, the wish of all wishes..., build an active cable for the AKG c6x series caps that will work w/the c480 body *(or no body at all).
it doesn't exist (for all intents).  one fella used to build them, but no longer.

[fivefishdiy]

Thanks Nick for the welcome and your inputs! Much appreciated.

- "dongle" cables to cut down on space.  Instead of various I/Os and the room that the jacks require, think about a single 5pin output, either w/switchcraft mini's (ta5) or full sized 5pin XLRs.  then you have various breakout cables which you can market or leave to the cable makers (we have several wonderful companies here on the list making custom cables).  This way you can have balanced/unbalanced and any flavor of output from the preamp to recorder.

Okay... I investigated and this is doable.  Will offer this as an option for the rear panel.  Lemo style jacks and receptables, with BAYONET LOCKING connector.  One cable for 2-ch BALANCED inputs, and one cable for 2-ch BALANCED outputs. (of course, the breakout cable can be wired for 2-ch unbalanced inputs and unbalanced outputs, or whatever combination thereof.)

Due to physical constraints on the receptable (i.e. maximum panel thickness), I will not be able to install it on the sides... but the backs will be fine.

So the different options are:

- Bayonet Jacks on the Back
- XLRs on the Back
- XLRs on the Sides

.... still don't know how to address the RCA outs or mini stereo (i.e. room on the rear panel)... but if you have the Bayonet jack, you can put whatever RCA or mini-stereo, 1/4" jack you want on the other end of the cable.

- as mentioned...lights are not all that relevant.  one to show its "on".  one to show that its "going to die"

Hmmm... haven't thought of the low-battery indicator. I'll see what I can do.

and one to show that its clipping, or close to it.  Many people like to run their gear "hot".  so a light at -2db would be perfect.  Lets us know what the box is doing before sending a signal out to a recording deck.

[/quote]

I assume you mean -2dB Full Scale (i.e. digital)... and not -2dBVU (analog).  Ok, a PRE-clip indicator...

build a preamp that can eliminate the need for the preamp body of these modular systems. 

If this unit does well, I'll look into that as a future possibility.

build an active cable for the AKG c6x series caps that will work w/the c480 body *(or no body at all).
it doesn't exist (for all intents).

Sorry for my ignorance. What's an active cable? a mic Pre in the jack of the mic?  on a cable?

[ero3030]

very nice!! love the side xlr's. just keep the powering easy,  and it will be a winner!!  ed

[Todd R]

Some thoughts on packaging:

If you use something like a 5-pin mini-XLR or LEMO jack on the back, make sure those connectors have matching cable ends that can be right-angle.  That is, you can get a neutrik RA 5pin XLR, but you can't get right-angle mini-XLR cable ends, and I don't know about LEMO parts.  At 6" deep, people using typical field bags will not have much room available for straight cable ends and will want RA.

If you want to stay with side connectors and the XLRs are hard to install on the case, you might think about using switchcraft mini-XLRs (Tini Q-G, TA-3F or TA-3M):

http://www.switchcraft.com/products/connectors-23.html

The TB3M panel mount connector might be able to fit on the side of your blue case without too much hassle.

Of course, you might want to get feedback on this, since mini-XLRs are used a bit on taping equipment, but aren't as standard as XLRs.  So people buying your preamp with these will need new cables made.

The other thing I noticed is that the handles on the blue case take up a bit of real estate.  You might want to consider leaving them off and freeing up this room for switches, etc.  I'm not sure how folks would feel about not having this protection.

I also wasn't sure what the various switches you have on the mock up for the blue case.  It might be possible to find some different switches that take up a lot less room.  I'm thinking about mini toggle switches like on the Grace Lunatec V3 of the mini slider switches like on the side of the Sound Devices 722 (which also shows the TB3M mini-XLR outputs):



This might leave enough room up front for more LEDs, or even an 1/8" mini output (so you could have XLR outputs on the side and the mini-out on the front).

[midside]

Another vote for a lemo/binder version so I can run my Schoeps actives.
Here's some features I would like to see and in my opinion would make your box a stellar unit:

1. lemo/binder connections to power active caps
2. all connections on 1 side
3. power loop, I would love to send battery power to this unit and come out to my SD7XX without using a splitter.
4. in conjunction with #3, good clean powering at 6.8-7.6 volts
5. a 4 channel version

The sonosax SX-M2/LS2, while a nice little box fails (IMO) with the power requirements.
At 12 volts, there is not much headroom, it really wants 16-24 volts.  But, it also sucks power quickly.
If you could offer a box that would run nice and clean at ~7V, power active caps and pass through power to a recorder, you will be miles ahead of everything else out there!!!

[fivefishdiy]

Todd, thanks for that tip!  That is a great tip!

I'm ordering some mini Switchcraft jacks to see how big they are... their website doesn't give much info on the more important details like dimensions. 

But looking at the pic... it *may* work... the only thing I find weird is their male jacks are circular, but the female jacks are not available in the same  form factor (instead it comes with the square flange). Anyways, I'm ordering samples to investigate that further.

The cost though is 3X the normal XLR jack. We're talking $36 already just for the (4) mini jacks alone. Hmmm....

Okay, so we'll have the following ordering options...
a) XLRs on the back
b) mini-XLRs on the side
c) Lemo/Binder jacks on the back

the handles on the blue case take up a bit of real estate.  You might want to consider leaving them off and freeing up this room for switches, etc.

I kinda like the look of the handles... leaving it off makes the unit look drab and exposed. But yes, they take up a lot of space....
There's the future possibility of making custom handles that will get attached using the existing 2 screws on each side of the front plate.

It might be possible to find some different switches that take up a lot less room.

Yes, those switches will get changed with a more smaller switch... 5mm diameter.  These are just mockups to see how the box will typically look.


midside

I'm still not sure what's an active mic, so I don't think my lemo/binder jacks will work with those.  I don't know... Does it require extra circuitry inside the preamp box for these active capsules to work?  Are these Electret condenser mics? kinda like the Panasonics? Do they require other voltages other than 48V? 

Do you have a website link explaining these kind of things?


QUESTION

Where does the DC Jack typically go?  And do you use some sort of binding post to wrap the cord around it so the jack doesn't get pulled out? What kind of protection does your unit uses to prevent pullout of the DC plug? 

[bluegrass_brad]

the apogee units use a cord holder tightened by a screw.

[ero3030]

if there is room,  xlr 4 pin for power.  ed

[midside]

Basically, Schoeps (as well as other manufacturers) have modular systems where different microphone capsules can be interchanged on the microphone bodies.  Ideally, these capsules run on 62V while the bodies are supplied with the standard 48V.  I don't technically know what it takes to properly power the capsules, but I do know that the circuit in the body is very small and looks simple enough.
Here's a link:
http://schoeps.de/E-2004/cmc.html
Other members here should be able to give you a schematic of the circuit in the mic body.
At near $1000 a body:
http://posthorn.com/S_cmc.html
you can see why a box that would let us bypass this would be desirable.
I'm positive that many members here would be very happy with this option!
OK people, chime in and back me up on this one....this is what we want....right?

[Brian Skalinder]

OK people, chime in and back me up on this one....this is what we want....right?

Great option, but I think supporting modular caps directly from the preamp - without the mic bodies - is a very small niche.  The Sonosax SX-M2/LS and /LS2 has been available for a long time (though not any longer, it seems) and will work with at least Schoeps MK-x caps and Neumann AK-xx caps (and maybe AKG CK-x caps? though I think the issue here is availability of the male threaded adapter to screw into the cap), yet not many people use them.  And I don't think it's because of the Lemosax's power requirements.  I think there's just not much demand;  it's a very niche requirement.  $0.02

[illconditioned]

Re: breakout cables.

If you can, please stay away from LEMO.  These are hard to find, and expensive.

If you make power and/or mic and/or line i/o out of XLR or miniXLR, lots of the "cable guys" on this forum can build cables for different people's needs.  This means you can focus on the box, and not worry about individuals' needs (various power supplies, right angle vs straight connectors, etc).

Another point, as others have shown, is copying ideas from existing units.  For example, copying the standard 4-pin XLR power connector is a good idea.  I'm not sure what units use this, but it seems to be popular, at least with the crowd here.

Finally, about the "actives".  I would just focus on the preamp for now.  Perhaps you can offer special options later, but if you build a great field-power preamp with more or less standard connectors, that gives you the most potential in sales.

Keep up the good work.

  Richard

PS: Finally, you *might* want to offer kits once you get everything done.  There are people, myself included , who would love to just solder this thing up if you gave the case and all the parts.

[Todd R]

4pin XLRs for power are nice, but it doesn't seem they are in use that much these days on field equipment, maybe either because lead-acid ecocharge batteries aren't used as much or because the 4pin connector takes up a lot of real estate.

Another possibility is a locking coaxial connector like the switchcraft s760k:

http://www.switchcraft.com/products/jack-146.html

Which means for your preamp you'd need something like:

http://www.partsexpress.com/pe/showdetl.cfm?&Partnumber=090-488

For cases, if you wanted to make a more custom size (like 8" wide and only 5 or 5.5" deep), maybe something like the 175DT option here would work:

http://www.enclosuresandcases.com/dtspecpage.html



This might allow a wider, shallower case that allows more real estate on the front and back for connectors, switches, and gain pots.

BTW, it seems that gear using the mini-XLR connectors use the male connector TB3M for both inputs and outputs.

[Scooter]

Lookin' good man +T.   I'm with Todd on the 4pin XLR's.  I know they are/were industry standard and all, but they seemed overly expensive and large.  I did like the switchcraft locking jack that he links to above, ala my old MP-2.

[fivefishdiy]

Bluegrass

Thanks for that pic. <thumbs up!>

midside

I don't own any of those kind of mics or capsules, so it will be hard for me to design for them... impossible or no way for me to test it and play with it.  Maybe sometime in the future... if I can figure it out.  From the description on their website, it's either the mic circuitry that's been moved outside the mic case into the preamp box, or some sort of an Active DI circuit.  So maybe I'll file this away and will look at it some more at a later time.


illconditioned

If you can, please stay away from LEMO.  These are hard to find, and expensive.

Oh man, I thought Lemo and Binder are the same company.  Yikes, LEMO is even more expensive than Binder.

If you make power and/or mic and/or line i/o out of XLR or miniXLR, lots of the "cable guys" on this forum can build cables for different people's needs.

The miniXLR is showing some promise... ordering some this afternoon and we'll see how it goes.  If I can find a different kind of case that will allow easy machining (either by the factory or me in the garage with my CNC), then full-size XLR holes on the side will be a possibility.

Keep up the good work.

Thanks!


Todd R

Another possibility is a locking coaxial connector like the switchcraft s760k:
http://www.switchcraft.com/products/jack-146.html
Which means for your preamp you'd need something like:
http://www.partsexpress.com/pe/showdetl.cfm?&Partnumber=090-488

Perfecto Mundo!  I like it. Price is reasonable, functionality high. <thumbs up>  Thanks for the links!

For cases, if you wanted to make a more custom size (like 8" wide and only 5 or 5.5" deep), maybe something like the 175DT option here would work:

Schweeeeet! Now we're talking. The plain flat sides will make mounting of full size XLR holes easy... and the breakable box means I can even mill and machine all the panels in my garage CNC, instead of having the factory do it.

This case OPENS UP (pardon the pun) a lot of possibilities. I can stick every kind of jack on every panel on this thing!

Great find! Thanks for the link.

[drpro]

I would also like to suggest Hirose connectors, less expensive than Lemo, Binder, or Fischer.   SD uses the small HR10 series for their recorders power inputs.  This connector is very common in the broadcast camera world. 

I notice that you live in the Brentwood area, I am in east Nashville and have a selection of Schoeps mics, capsules and cables if you would like to try them out.

David
drpro@sonusclarus"period"com